function b=mdsiocompact(a);
  % hack to convert to mdsio compact format
  
  [nx,ny,nz,nt]=size(a);
  if nx/4~=round(nx/4);
    error('not a llc field');
  end

  n4=nx/4;
  m=(ny-n4)/n4;
  m4=m*n4;
  for kt = 1:nt
    for kz = 1:nz
      for k=1:4
	sides{k} = a([1:n4]+(k-1)*n4,1:m4,kz,kt);
      end
      cap = a([1:n4]+1*n4,m4+1:end,kz,kt);
      % reformat
      btmp = [sides{1} ...
	      sides{2} ...
	      cap ...
	      reshape(rot90(sides{3},1),[n4 m4]) ...
	      reshape(rot90(sides{4},1),[n4 m4]) ...
	      cap*0];
      b(:,:,kz,kt)=btmp;
    end
  end
  
  return